The travel times of solutes at the Cape Cod Tracer Experiment: Data analysis, modeling, and structural parameters inference

A method for analyzing and interpreting travel times of solutes in heterogeneous aquifers is presented based on the peak concentration arrival times as measured at various samplers in the aquifer. The method allows separation of the effects of pore-scale dispersion from the effects of the large-scale aquifer heterogeneity. An analysis of data from the Cape Cod field experiment is presented, and we found that the values of the hydrogeological parameters inferred from the travel times match very well the values obtained from direct interpretation of cores. Analysis of the spatial correlations of the travel times also allows inference of spatial covariances of the log conductivity and the anisotropy ratio of the correlation lengths. Separate analyses of the travel times carried over planes at different travel distances show that the variance of the log conductivity increases with travel distance.